Hammer locking arrangement for impact crusher rotor

ABSTRACT

An impact crusher is disclosed having a rotor carrying a pair of hammer bars, with each hammer partly within an axially extending peripheral slot diametrically opposite each other. A portion of each leading hammer face within the slot and a facing wall of the slot cooperate to define therebetween a generally cylindrical cavity parallel to an axis about which the rotor rotates. A twopiece bushing is fitted in the cylindrical cavity at each end of the rotor, and each of the bushings comprises a pair of bushing halves each having a convex semi-cylindrical outer surface. The bushing halves are arranged within the cylindrical cavity with one convex surface engaging the hammer defined portion of the cavity and the other convex surface engaging the slot wall defined portion of the cavity, and with a diametrical plane along which the bushing is split into halves, being substantially parallel to the adjacent leading hammer face. The halves of each bushing define therebetween an internal conical shaped cavity with an apex end pointed inwardly of the adjacent end of the rotor. A frusto-conical plug is inserted into each bushing with apex ends pointed inwardly of adjacent ends of the rotor. A rod passes through central bores in both plugs, and nuts threaded on both rod ends hold the plugs relative to each other. Retaining walls are provided within the cylindrical cavity to limit movement of the bushings inwardly of their respective adjacent rotor ends. Movement of the frusto-conical plugs toward each other therefore moves each pair of bushing halves apart. As each pair of bushing halves move apart their convex outer semicylindrical surfaces move apart and apply forces which are directed radially of the bushings to both push the hammer radially into its slot and tangentially against the back wall of the slot, to securely lock the hammer in its slot.

United: States Patent Lowe et al.

1 HAMMER LOCKING ARRANGEMENT FOR IMPACT CRUSHER ROTOR [75] Inventors:Keith B. Lowe; William R. Gray,

both of Appleton, Wis.

[73] Assignee: Allis-Chalmers Corporation,

Milwaukee, Wis.

22 Filed: Jan. 16,1974

21 Appl. No: 433,882

Primary Examiner-Roy Lake Assistant E.\'un1inerE. F. Desmond Attorney,Agent, or Firm-Arthur M. Streich [57] ABSTRACT An impact crusher isdisclosed having a rotor carrying a pair of hammer bars, with eachhammer partly within an axially extending peripheral slot diametricallyopposite each other. A portion of each leading hammer face within theslot and a facing wall of the slot cooperate to define therebetween agenerally cy- [111 3,874,603 [451 Apr. 1, 1975 lindrical cavity parallelto an axis about which the rotor rotates. A two-piece bushing is fittedin the cylindrical cavity at each end of the rotor, and each of thebushings comprises a pair of bushing halves each having a convexsemi-cylindrical outer surface. The bushing halves are arranged withinthe cylindrical cavity with one convex surface engaging the hammerdefined portion of the cavity and the other convex surface engaging theslot wall defined portion of the cavity, and with a diametrical planealong which the bushing is split into halves, being substantiallyparallel to the adjacent leading hammer face. The halves of each bushingdefine therebetween an internal conical shaped cavity with an apex endpointed inwardly of the adjacent end of the rotor. A frusto-conical plugis inserted into each bushing with apex ends pointed inwardly ofadjacent ends of the rotor. A rod passes through central bores in bothplugs, and nuts threaded on both rod ends hold the plugs relative toeach other. Retaining walls are provided within the cylindrical cavityto limit movement of the bushings inwardly of their respective adjacentrotor ends. Movement of the frusto-conical plugs toward each othertherefore moves each pair of bushing halves apart. As each pair ofbushing halves move apart their convex outer semicylindrical surfacesmove apart and apply forces which are directed radially of the bushingsto both push the hammer radially into its slot and tangentially againstthe back wall of the slot, to securely lock the hammer in its slot.

1 Claim, 2 Drawing Figures AIENIEB APR 1 I975 SHEET 1 [IF 2 PATENIEDAPR1 I915 sum 2 [IF 2 HAMMER LOCKING ARRANGEMENT FOR IMPACT CRUSHER ROTORBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to impact crushers which have a rotor carrying hammers arrangedto strike and throw rock to disintegrate upon impact with target membersspaced from the rotor, and in particular to an improved arrangement forattaching hammers to the rotor.

2. Description of the Prior Art It has long been known to provide therotor of impact crushers with easily replaceable hammers, by insertingthe hammers endwise into axially extending peripheral slots which in endview appear as a dovetail (or partial dovetail), and with centrifugalforce acting to wedge the hammers into seating engagement with slotwalls. An example of such a crusher is the machine shown in a patentassigned to Allis-Chalmers Manufacturing Company, U.S. Pat. No.1,331,969 of Feb. 24, 1920. However, as explained in U.S. Pat. No.2,310,758 of Feb. 9, 1943, it was considered desirable to hold suchhammers against very large centrifugal forces, by clamping arrangementsacting with dovetail slots and having bolts in a plane perpendicular tothe rotor axis. Other U.S. Pat. Nos. disclosing such arrangementsinclude 2,747,803 of May 29, 1956; 2,767,928 of Oct. 23, 1956; 2,862,669of 1958', and 3,151,816 of 1964.

Another clamping arrangement for holding hammers in dovetail slots,involves members having wedging stirfaces and movable by bolts parallelto the rotor axis. There are many U.S. Pat. Nos. showing sucharrangements, including 2,192,606 and 2,223,584 of 1940; 2,258,075 of1941; 2,325,605 of 1943', 2,373,691 and 2,378,475 of 1945; 2,585,943 and2,588,434 of 1952; 2,646,224 of 1953; 3,096,035 of 1963; 3,146,961 of1964; 3,295,773 of 1967; and 3,455,517 of 1969.

As will appear from the description ofthe present invention to follow,the object of the present invention is to provide a new and improvedarrangement of the last mentioned type. Of the prior patents referred toperhaps the most pertinent to the present invention is U.S. Pat. No.2,258,075 of Oct. 7, 1941. This prior patent shows several arrangementsincluding one in which a pair of conical members are drawn toward eachother along an axis parallel to the rotor axis, to lock hammers withrotor slots.

SUMMARY OF THE PRESENT INVENTION According to a preferred embodiment ofthe present invention an impact crusher is provided with a rotorcarrying a pair of hammer bars with each hammer partly within an axiallyextending peripheral slot diametrically opposite each other. A portionof each leading hammer face within the slot and a facing wall of theslot cooperate to define therebetween a generally cylindrical cavityparallel to an axis about which the rotor rotates. A two-piece bushingis fitted in the cylindrical cavity at each end of the rotor, and eachof the bushings comprises a pair of bushing halves each having a convexsemi-cylindrical outer surface. The bushing halves are arranged withinthe cylindrical cavity with one convex surface engaging the hammerdefined portion of the cavity and the other convex surface engaging theslot \vall defined portion of the cavity, and with a diametrical planealong which the bushing is split into halves, being substantiallyparallel to the adjacent leading hammer face. The halves of each bushingdefine therebetween an internal conical shaped cavity with an apex endpointed inwardly of the adjacent end of the rotor. A frustoconical plugis inserted into each bushing with apex ends pointed inwardly ofadjacent ends of the rotor. A rod passes through central bores in bothplugs, and nuts threaded on both rod ends hold the plugs relative toeach other. Retaining walls are provided within the cylindrical cavityto limit movement ofthe bushings inwardly of their respective adjacentrotor ends. Movement of the frusto-conical plugs toward each othertherefore moves each pair of bushing halves apart. As each pair ofbushing halves more apart their convex outer semi-cylindrical surfacesmove apart and apply forces which are directed radially of the bushingsto both push the hammer radially into its slot and tangentially againstthe back wall of the slot, to securely lock the hammer in its slot.

Other features and objects of the invention that have been attained willappear from the more detailed description to follow with reference to anembodiment of the present invention shown in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I of the drawings is a view inelevation and partly in section, showing an impact crusher according tothe present invention: and

FIG. 2 is an exploded isometric view of a rotor for the crusher shown inFIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, an impactcrusher is shown which comprises a housing I having disposed within alower area thereof a rotor 2 mounted on a shaft 3 which is carried bysuitable journal bearings 4. The housing 1 defines a material feedopening 5 over a feed chute 6 inclined downwardly toward the rotor 2.The feed chute 6 delivers rock to hammers 7 and 8 which are carried bythe rotor 2 in a manner which will hereinafter be described in detail.

Chute 6 directs feed rock to rotor 2 at a location where its hammers 7and 8 are ascending with the result that the impact of hammers 7 and 8on rock breaks the rock into smaller particles which are thrown upwardlyto break into even smaller particles upon impact with a complement ofprimary target breaker bars 12 and 13 which are carried by the casing I.A secondary crushing occurs when such particles drop downwardly frombars 12 and 13 to be again struck by hammers 7 and 8 and thrown toward adischarge area 14 where the particles impact with a vertical array ofsecondary target bars 15. Close to the periphery of rotor 2, one or moreadjustable and yieldable breakerbars I6, 16' may be arranged. Adjustableand yieldable mounts such as for bars 16, 16 are well known and oneexample of such mounts is shown in U.S. Pat. No. 2,486,421 of Nov. 1,1949. Any particles not passing between the bars 15 and into dischargearea 14, progress downwardly toward the bar 16' where such particles aresubjected to a final crushing as the particles are nipped and urgedthrough the space between rotor 2 and bar 16' to the lowest portion ofthe discharge area. The casing I may include a pivotal portion 18connected to base structure 19 by a hinge 20, operative to open thecasing and provide access to the internal mechanisms.

The rotor 2, shown in elevation in FIG. 1 and the exploded isometric inFIG. 2, will now be described. The rotor may be thought of as comprisingan elongated central body portion 23 with a pair of axially extendingslots 24, 25 and a pair of diametrically opposed spiral body extensions26, 27. With reference to FIG. 2, slot 24 is shown as having a leadingwall 28, a floor 29 and a back wall 30. The body extensions 26, 27 eachproject progressively farther radially outward beginning at leading wall28 of one slot and reaching maximum radial projection at a terminusdefining a face 31 planar with back wall of the other slot.

First and second hammer means, shown in both FIG. 1 and FIG. 2 as thehammer bars 7 and 8, are each arranged in one of the slots 24, 25, andproject outwardly of such slots with a leading hammer face 34 extendingoutwardly and terminating with an edge 35 outward of slot edge 28 atleast as far the radially outer edge of the face 31.

Referring now again to FIG. 2, a radial inner surface portion 38 of theleading hammer face 34 of bar 7, is shaped to define a concavesemi-cylindrical cavity. The leading slot wall 28 is also shaped todefine a concave semi-cylindrical cavity. The surface 38 and the wall 28therefore cooperate in the assembly to define therebetween a generallycylindrical cavity 28, 38 parallel to shaft 3. A two-piece bushing 39,40 is provided for insertion in the cylindrical cavity 28, 38 at eachend thereof. The two bushing pieces 39, 40 are each halves of a completebushing and each have a convex semicylindrical outer surface 41, 42,respectively. The two bushing pieces 39, 40 each also have an innerconcave surface 43, 44, respectively, which together define afrusto-conical cavity. A frusto-conieal plug is provided for eachbushing 39, 40 and each plug 45 conforms to the shape of thefrusto-conical cavity defined by bushing surfaces 43, 44. Each plug 45has a central bore 46 through which a rod 47 may be inserted. The rod 47is threaded on both ends for engagement with threaded nuts 48, 49.

In the assembly of rotor 2, hammer 7 for example is placed in slot 24 onfloor 29 and abutting against back wall 30, with wall 38 and surface 38thereby cooperating to define therebetween a generally cylindricalcavity. One of the two-piece bushings 39, 40 is inserted from each endof the rotor 2 with apex ends of the inner frusto-conical cavities 43,44 pointed inwardly of adjacent rotor ends. The bushings 39, 40 aremoved inwardly until the pieces abut against semi-annular retainingwalls 50, 51 in the cavity defined by slot wall 28 and semi-annularretaining walls 52, 53 in the cavity defined by surface 38. Theretaining walls -53 limit movement of the bushings inwardly theirrespective adjacent rotor ends. With the two-piece bushings 39, 40 eachabutting against a pair of retaining walls 50, 52 and 51, 53,respectively, the bushing surface 41 is aligned to engage hammer surface38 and bushing surface 42 is aligned to engage slot wall surface 28,preferably with a diametrical plane XX' (see FIG. I) along which thebushing is split into the halves 39, 40, being substantially parallel tothe adjacent slot back wall 30. Referring again to FIG. 2, thefrusto-conical plugs 45 are aligned with their apex ends pointedinwardly, and each is inserted into one of the bushing cavities definedby surfaces43, 44. The rod 47 is then inserted through the bores ofplugs 45 and the nuts 48, 49 are secured to its ends. i

In the operation of the described assembly to secure a hammer, suchhammer 7, as the plugs 45 are driven in their respective bushings 39,40, the plugs 45 are moved inwardly toward each other. As plugs 45 movetoward each other, the bushing halves 39, 40 surrounding each plug 45move apart. Finally, as bushing halves 39, 40 move apart, their convexsemi-cylindrical outer surfaces 41, 42 move apart and apply forces whichare directed radially of the bushing halves 39, 40 to both push hammer 7radially toward shaft 3 and into its slot 24, and push hammer 7tangentially with respect to the central body portion 23 of rotor 2,against the back wall 30 of slot 24, to securely lock the hammer 7 inits SlOt 24.

From the foregoing detailed description of the present invention it hasbeen shown how the object of the present invention has been attained ina preferred manner. However, modification and equivalents of thedisclosed concepts such as readily occur to those skilled in the art areintended to be included in the scope of this invention. Thus, the scopeof the invention is intended to be limited only by the scope of theclaims such as are or may hereafter be, appended hereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A hammer rotor for an impact crusher having an elongated central bodyportion with at least a pair of axially extending peripheral slotsdiametrically opposite each other and extending the entire axial lengthof the rotor, and first and second hammer means each comprising a hammerbar arranged in one of said slots with a portion of a leading hammerface within said slot and a portion thereof extending outwardly of saidslot, characterized by:

a. portion of the leading hammer face within the slot and a facing wallof the slot cooperating to define therebetween a generally cylindricalcavity parallel to an axis about which the rotor rotates;

b. a pair of bushing assemblies in said cylindrical cavity with onelocated at each end of the cavity and with each said bushing assemblycomprising a pair of separate semi-cylindrical bushing halves eachhaving a convex semi-cylindrical outer surface, with the convex surfaceof one semi-cylindrical bushing half engaging the hammer defined portionof the cylindrical cavity and the convex surface of the othersemi-cylindrical bushing half of such a pair engaging the slot walldefined portion of the cylindrical cavity, and said pair of bushinghalves cooperating to define therebetween an internal conical shapedcavity with an apex end pointed inwardly of the adjacent end of therotor;

c. A frusto-conical plug within each pair of said bushing halves andarranged with its apex end also pointed inwardly of the adjacent end ofthe rotor, and movable inwardly of the adjacent end of the rotor; and

d. a threaded rod projects through both plugs for engaging meansoperative to hold the plugs in a position applying uniform lockingforces at both ends

1. A hammer rotor for an impact crusher having an elongated central bodyportion with at least a pair of axially extending peripheral slotsdiametrically opposite each other and extending the entire axial lengthof the rotor, and first and second hammer means each comprising a hammerbar arranged in one of said slots with a portion of a leading hammerface within said slot and a portion thereof extending outwardly of saidslot, characterized by: a. portion of the leading hammer face within theslot and a facing wall of the slot cooperating to define therebetween agenerally cylindrical cavity parallel to an axis about which the rotorrotates; b. a pair of bushing assemblies in said cylindrical cavity withone located at each end of the cavity and with each said bushingassembly comprising a pair of separate semi-cylindrical bushing halveseach having a convex semi-cylindrical outer surface, with the convexsurface of one semi-cylindrical bushing half engaging the hammer definedportion of the cylindrical cavity and the convex surface of the othersemicylindrical bushing half of such a pair engaging the slot walldefined portion of the cylindrical cavity, and said pair of bushinghalves cooperating to define therebetween an internal conical shapedcavity with an apex end pointed inwardly of the adjacent end of therotor; c. A frusto-conical plug within each pair of said bushing halvesand arranged with its apex end also pointed inwardly of the adjacent endof the rotor, and movable inwardly of the adjacent end of the rotor; andd. a threaded rod projects through both plugs for engaging meansoperative to hold the plugs in a position applying uniform lockingforces at both ends of the hammer.